Any ingredient that improves the properties of a pesticide formulation (Pedigo 2002). Any ingredient that improves the solubility or handling properties of a pesticide formulation. Adjuvants are sometimes called “stickers” or “spreaders” (Gordh and Headrick 2001). An additive used in conjunction with an active substance, e.g. a biopesticide, to enhance its performance (Coombs and Hall 1998). Chemical combined with insecticide to improve its storage, safety, or effectiveness (Daly et al. 1998). A spray additive to improve either physical or chemical properties (Hill 1997). See ‘chemical control’.